8.2.1
Circular Dichroism and Synchrotron Radiation Circular Dichroism
Circular dichroism and synchrotron radiation circular dichroism (SRCD) have been resorted to in
a score of studies (Table 8.1). A very frequent use is to assess the secondary structure of MPs that
have been folded or refolded in APols. This is illustrated by the CD spectra of two β-barrel MPs
shown in Fig. 8.2 (from Study 8.4) and the SRCD spectra of an α-helical MP shown in Fig. 8.3 (from
Study 8.9).
Optical spectroscopy of membrane protein/amphipol complexes
(# 2018 by Francis Haraux)
Fig. 8.2 Circular dichroism spectra of two β-barrel MPs, OmpA (left) and FomA (right), either unfolded
in urea or after refolding in A8-35. CD spectra of OmpA and FomA folded in lauryldimethylamine oxide
(LDAO), which are similar to those of the native proteins, are shown for comparison (Reprinted with
permission from Pocanschi et al. 2006, # 2006 American Chemical Society).
8.2 Optical Spectroscopy Studies of Amphipols and Membrane Protein/Amphipol Complexes
391